The present invention relates to a railroad car for transporting at least one cylindrical object with its axis transverse to the direction of travel of the car. The present invention also relates to a telescoping cover assembly for a railroad car. The cover is movable between a first position on the car covering the entire cargo bed and a second position on the car uncovering the entire cargo bed at once.
Large, heavy cylindrical objects, and particularly coils of rolled steel, are commonly transported on a flatcar or a troughed car. Either type of car has a cargo bed supported on a center sill or similar structure running the length of the car. The individual coils are chained or otherwise restrained in place. In some cars of this type, the coils are carried with their axes longitudinal with respect to the direction of travel of the car. Examples of this arrangement are U.S. Pat. Nos. 2,494,404, issued to Nixon on Jan. 10, 1950 (which shows a semi-trailer, instead of a railroad car) and 3,291,072, issued to Cunningham on Dec. 13, 1983. In other instances, the coils are carried with their axes transverse to the direction of travel of the car. Examples of this construction are U.S. Pat. Nos. 3,291,073, issued to James on Dec. 13, 1966; 1,850,597, issued to McGuire on Mar. 22, 1932; and 3,715,993, issued to Orlik on Feb. 13, 1973 (in which the cylindrical objects are cable reels).
When the coils are carried with their axes longitudinal to the direction of the car, the coils can move longitudinally in the bed due to acceleration, deceleration, or yard impacts. The interior turns of the coils can also extend or telescope axially out of the coils responsive to the same forces. (In relation to steel coils, "telescope" here means that the inner coils extend out of line with the outer coils. Respecting the sections of a cover, "telescope" means that the covers are shifted to an overlapping relation.) To alleviate these types of longitudinal movement, the prior art has placed transverse bars forward and aft of each coil. However, the weight of a steel coil is so great that the coil or its inner turns may shift longitudinally against the transverse bar. The steel is soft enough that the bar can be impressed on the exposed edges of the coil and even embedded in the coil, preventing the coil from being lifted vertically out of the car. Such engagement of the steel coil with the transverse bar damages or even ruins the metal of the coil. This problem is discussed in the James ' 073 patent cited above.
Cylindrical objects such as steel coils have also been carried transversely in troughs. Each trough has facing, inwardly inclined surfaces which support the coil. The transverse orientation of the coil prevents the inner turns from telescoping and centers the coil on the trough, preventing both forms of shifting. A disadvantage of such troughs is that some or all of the troughs and coils are supported above the center sill or similar structure for handling draft and buff loads. A flatcar does not allow the coils or troughs to project below the center sill of the car.
An example of a European coil steel car, which supports one of several coils very slightly lower than the tops of the side sills of the car, is shown on page 41 of the DB Guterwagen brochure. That brochure does not illustrate a center sill. The side sills are massive and accept the buff loads directly through the buffers at each end of the car. Since the date of the brochure and the extent and manner of its distribution are not fully known, it is not admitted to be prior art.
At least two disadvantages result from supporting the cylindrical objects high on the car. One disadvantage is that the center of gravity of a loaded car is substantially above the coupler level. A car loaded high is more subject to rocking and rolling, and when the car collides with another car in a switching yard the opposite end of the car tends to pitch upward. This jostles the coils vertically, which may damage either the coils or their supports. Another disadvantage is that the covers provided for the car to protect the steel coils from the weather must be taller than the largest coils to be transported by the car, enclosing a large volume of air around the coils. The large size of the covers makes them quite heavy. The large enclosed volume beneath the covers, including the volume enclosed from below by the cargo bed, increases the amount of atmospheric moisture available to condense on the coils, thus increasing the amount of rust formed on the coils.
Another problem in the art is that the troughs contribute little support to the structure of the car. The car must have independent means to accept the draft and buff loads of a railroad train, as well as transverse and vertical structure to stiffen the car. This problem is particularly acute when the troughs are defined by pallets which are removable from the car with the coils.
Well cars which have no center sill, and which transmit longitudinal loads from the couplers and draft sills through side sills, top chords, and other longitudinal members beside or beneath the cargo bed, are known. One example of such well car construction is U.S. Pat. No. 4,841,876, issued to Gramse et al. on Jun. 27, 1989 FIGS. 2-6, 9, and the corresponding parts of the specification of that patent are hereby incorporated herein by reference to show the transfer of longitudinal loads downwardly from the coupler level to the shear plates 60 and side sills (such as 38 in FIG. 9) of the car. We believe the well car plan of construction has not previously been used in a car dedicated to the transport of heavy cylindrical objects.
Another problem in the art has been how to cover a load on the cargo bed of a railroad car. In Europe, railroad cars are known which have a longitudinally telescoping cover. The cover is made in segments which travel on longitudinal rails on either side of the cargo bed. The segments may be extended to cover the entire load at once. Examples of this construction are U.S. Pat. Nos. 4,569,293, issued to Kramer et al. on Feb. 11, 1986; and 4,341,163, issued to Ritzi on Jul. 27, 1982. Telescoping doors having some features in common with sliding covers are disclosed in U.S. Pat. Nos. 3,815,518, issued to Schreider et al. on Jun. 11, 1974; 3,828,693, issued to Kampmann, et al. on Aug. 13, 1974; and 3,999,489, issued to Kramer et al. on Dec. 28, 1976. Typically, the cover mates with fixed bulkheads on each end of the car to complete a cover which is relatively weatherproof.
However, in known cars with telescoping covers, even if the cover is fully telescoped for unloading the car, at least part of the cargo bed is still obstructed by the cover. Thus, the cover must be fully telescoped at one end of the car, following which the opposite end of the car is unloaded, the telescoped cover assembly is moved on its rails to the unloaded portion of the car, and the remaining portion of the car is unloaded. Thus, many operations must be performed in sequence to unload the car. It would be simpler to uncover the car entirely in a single step, then unload it in a single step.
The prior art has been able to follow this simpler procedure only when the covers are removable from the car, in which case they must be lifted off with a crane and stored somewhere before the car is unloaded. Removable covers are disclosed in U.S. Pat. No. 3,994,240, issued to Berg et al. on Nov. 30, 1976.
Thus, one has had to choose between 1) covers which must be removed to expose the complete cargo bed, and 2) telescoping cover assemblies which cannot uncover the entire bed at once for unloading.